The runway equipment for the MLS usually includes four transmitting stations which are distributed around the runway in a particular manner and transmit on the same frequency in a predetermined time sequence. Each transmitting station has a main transmitter and a stand-by transmitter, an antenna changeover switch, and various antennas. To improve the reliability of operation, the duplicate devices are frequently operated simultaneously and monitored separately. The power outputs must then be switchable to the load and to a dummy load and sufficiently isolated from each other. The dummy load must be matched to the power outputs in the same manner as the load to be supplied, and must be able to absorb the same power. In addition, energy consumption is unnecessarily high. Such a transmitting station, though not designed for the MLS, is described by G. Bertocchi, "Elektrisches Nachrichtenwesen", Vol. 58, No. 3, 1984, pages 289 to 292, especially in the passage relating to FIG. 1.